单项选择题
A．giving a lot of lectures to students B．involving students in discussions C．asking students questions in class D．answering students' questions in class
A．learn how to do research and write papers B．have some learning experience C．learn about the course concretely and clearly D．know how to participate in discussions
A．how well they perform in class B．how carefully they prepare their lessons C．how fluently they express themselves in class D．how hard they work before and in class